The future’s so bright I gotta wear shades. Or perhaps it’s so dark you don’t even want to imagine it.

This is a topic which comes up from time to time, but the realities of genetic engineering, Crispr gene editing and the increasingly cheap cost of mapping of the human genome are presenting us with all sort of possibilities which are likely coming much sooner than we think. Things which only a few decades ago seemed like the stuff of impossible dreams or dystopian nightmares (depending on your outlook) are quickly coming within reach of current medical technology.

One of the most actively pursued subjects in this field is the idea of identifying the potential for diseases in children before they are born, and now, even before they are conceived. But it could go much, much further than that very quickly, where genetic editing could allow for a dizzying array of choices for prospective parents, and we’ll likely be seeing this in public use in the next 20 to 40 years. That’s the theory in a new book by Henry T. Greely, available from the Harvard Press.

Here’s a brief bit from the introduction which gives you a sense of where this is going.

Within twenty, maybe forty, years most people in developed countries will stop having sex for the purpose of reproduction. Instead, prospective parents will be told as much as they wish to know about the genetic makeup of dozens of embryos, and they will pick one or two for implantation, gestation, and birth. And it will be safe, lawful, and free. In this work of prophetic scholarship, Henry T. Greely explains the revolutionary biological technologies that make this future a seeming inevitability and sets out the deep ethical and legal challenges humanity faces as a result.

Developments in genetics and stem cell research are giving rise to new techniques that will vastly improve preimplantation genetic diagnosis (PGD) and in vitro fertilization (IVF), making sexless reproduction not just possible but cheap and easy—what Greely coins “easy PGD.” The first child born using PGD is now 25 years old, and thousands more are born each year. Advanced by economic, social, legal, and political forces, the emerging science has made the concerns that were once the stuff of science fiction into real problems that our children and grandchildren will face routinely.

Taken at face value, much of this sounds wonderful. I mean, who wouldn’t want to remove (or at least minimize) the chance of their child being born into a life of debilitating or even lethal disease? But this technology is also consumed with moral and ethical questions. Particularly in conservative camps, the premise of a couple producing one hundred (or even more) embryos in an external laboratory containment with a printout of the predicted characteristics of each, selecting one and discarding the rest is going to be similar to 99 abortions. But even if we get beyond that aspect of the question, how far do you want these choices to go?

Getting back to the title of this article, the book also informs us that pretty much all of the laboratory gene mixing can be done outside of the female’s body. In fact, within a decade or three you won’t even need sperm and an egg… they are close to being able to craft those for you out of skin cells. So there’s the really big news… sex won’t be required to produce a baby. How great is that, huh? (Egad)

With full mapping of the genome already in progress and being fully fleshed out more and more each year, you will be able to select for not only the gender of the child, but hair color, predicted height and weight, overall athleticism, and even… intelligence. Do we really want that level of control?

The societal effects will be stunning as well if this is in common use. Will everyone produce tall offspring to the point where a 5’10’ male will be looked upon as a freak of some kind in one or two generations? Gender selection is problematic also. There is a persistent perception that women not only earn less, but face higher levels of discrimination than men. Will too many parents simply deselect girls until the entire planet faces the problems that China and India have now with unequal gender distribution, but taken to a vastly larger degree?

It turns out that everyone has buried genes which control things like hair color. By turning on the right set of genes, two brown haired parents could produce a redhead for one example. But it goes even further, and genetic engineers theorize that even skin color and other external traits can all be turned on, shut off, or modified. Would people begin switching their kids to be white to give them a better shot in society? The possibilities are dizzying and alarming.

Exit question: how much control over all of this would you want? If you could shut off all of the genes leading to higher probabilities of cancer in your child I’m guessing you might do it. But what about the rest? How much of a “custom baby” would you be comfortable ordering from a menu?